Improvement in cut-off valves for steam-engines



SAMUEL? MQCAYRTERS mPRovto CUT-OFFVALVL Pawnee Aug. 22,3371.

' INVEN'TOR,

WITNESSESfl PATENT QFFICE.

SAMUEL MCOARTER, OF NORB'ISTOWN, PENNSYLVANIA.

IMPROVEMENT IN CUT-OFF VALVES FOR STEAM-ENGINES.

Specification forming part of Letters Patent No. 118,340, dated August22, 1871.

To all whom it may concern:

Be it known that I, SAMUEL MGGARTER, of N orristown, in the county ofMontgomery and State of Pennsylvania, have invented a certainImprovement in Gut-01f Valves for Steam-Engines, of which the followingis a specification:

My invention consists in a valve with a loose self-adjustable face, forthe purpose of saving steam by cutting the steam oif from the cylinderat half-stroke, more or less, as desired, and holding it in the cylinderon the piston to the end of the stroke without cramping the exhaust.

Figure l is a sectional side elevation,showing the openings in anordinary steam-cylinder with steam-chest, valve-seat, valve, and rod,850. Fig. 2 is a top view of the loose face P P, showing itsconstruction.

The loose face P P and piece V are fitted and ground together, andprovided with flanges l and l at the ends, for the purpose of allowingthe valve to lengthen and shorten itself at each end alternately whilein operation, and also to give to the loose face PP its proper movement.The loose face P P is provided with two openings, B and B, for admittingthe steam to the cylinder, and one opening, M, for exhausting it fromthe cylinder. This loose face P P is intended to move about one-half,(15,) more or less, of the distance moved by the piece V, and isdetermined by the space between the flanges l and Z. This loose face P Pis intended only to admit the steam to the cylinder through the openingsB and B, and to exhaust it from the cylinder after it has done its Workthrough the opening M into the exhaust-port E of the engine, while thepiece V is intended to cut the steam off from passing into the cylinderonly by moving over the openings B and B alternately, thus making thelead ing-on and cutting-off points independent of each other.

This valve,V and P P combined, can be made to cut the steam off from thecylinder at any desired point of the stroke and equally at both ends,

and hold it in the cylinder on the piston to the end of the stroke andthen exhaust freely, keeping open a wide communication with theexhaustport E, thus allowing the piston to return without being retardedin the least, thereby getting the full benefit of the expansive force ofthe steam on the opposite side or end of the piston.

The piece V can be set to cut off, without regard to leading-on orexhausting, as the loose face P P performs both these operations itselfwhen moved by the pieceV coming in contact with the flan ges l l, ortheir equivalent.

The position of the valve V P P, as shown in the drawing, is supposed tohave been drawn by the valve-rod to the end of its movement, admittingthe steam to the cylinder through opening Binto steam-channel 0. Now,the first movement from its present position would be for the valve-rodto force the piece V back, (the loose face P P standing still andholding open the exhaust with the steam-channel'ofl) pass over theopening B, and cut ofi the steam from passing into the cylinder through0, uncovering opening B, and then coming in contact with. flange I, movethe loose face P P until opening M leaves steam-channel 0, closing it,and opening communication between exhaust-port E and steam-channel 0,and admitting the steam to the other end of the cylinder by bringingopening B over steamchannel 0. The effect of the return movement of thevalve would, of course, be similar to that of the forward movement justdescribed.

I claim The combined valve V P P with self-adjustable face,provided withflanges Z l, or their equivalent, for the purpose of allowing the valveto shorten and lengthen itself at each end alternately while inoperation, substantially and for the purpose hereinbefore set forth.

SAML. MGGARTER.

Witnesses:

R. S. NEwBoLD, J. D. NEW'BOLD.

